Jeremy Lennert wrote on Thu, Apr 14, 2011 10:29 PM UTC:
'FAND is a special case. This piece not only 'can mate', it can mate all
by itself by force in an open position.'
This doesn't seem to be true. The only mating position for FAND unaided is K in a corner and FAND one A move away. But in order to force a K on b1 into a1, the FAND would need to threaten all of a2, b2, c2, and c1 (plus b1, if K's owner has other pieces), which it can only do from a0, which first of all is off the board, second of all is close enough for the K to capture it, and third of all is more than one move away from c3, where it needs to be to complete the mate.
WFND can mate unaided by threatening K with a D move and then duplicating K's moves until it is trapped on an edge. WFAN cannot, because K can move orthogonally to the threat.
This doesn't seem to be true. The only mating position for FAND unaided is K in a corner and FAND one A move away. But in order to force a K on b1 into a1, the FAND would need to threaten all of a2, b2, c2, and c1 (plus b1, if K's owner has other pieces), which it can only do from a0, which first of all is off the board, second of all is close enough for the K to capture it, and third of all is more than one move away from c3, where it needs to be to complete the mate.
WFND can mate unaided by threatening K with a D move and then duplicating K's moves until it is trapped on an edge. WFAN cannot, because K can move orthogonally to the threat.